Step 1: Preparing the Keg for speaker.

You need to find an old speaker that still works and remove it from its enclosure-preferably a good brand name but any speaker will work. Just make sure it can handle the power your amplifier puts out. Then you cut hole in top of can and on side of can for the speaker and speaker wire terminal block(see drawing)

Step 2: Prepare speaker for installation

In this step you will hook up the speaker wires from speaker to terminal block, add insulation to bottom of can to dampen sound and glue speaker to top of can.

Step 3: Start listening

Now you hook up your "Bubba Sub" to your amplifier or stereo and start listening to your tunes.

looks cute, but how is the sound working out for you? i would imagine you are running into a problem with vibrations in the canister with no horn. A horn will improve the sound quality produced by your driver and give some phase control.

For larger speakers and a deeper bass response you could go on Ebay and buy a 10 (9.5) gallon screw top plastic barrel or even a plastic 55 gallon barrel for the ultimate pickup back REDNECK gheto blaster.